We don't eat raised bread (like that pictured at right) on Passover for reasons that may surprise you – especially if you learned history from a gemara in a haredi yeshiva or from a local community Hebrew school.
The Real Reason We Eat Matzah On Passover
Shmarya Rosenberg • FailedMessiah.com
Wild wheat – Einkorn – was eaten by early man as far back as 10,000 years ago. The neolithic hunter found murdered and frozen in the ice on the Italian Alps several years ago had the remains of a soft Einkorn flatbread frozen in his stomach. He was killed about 5,300 years ago.
Einkorn has 14 chromosomes.
It's successor, Emmer, a cross breeding of Einkorn and Goat Grass that probably occured naturally, has 28 chromosomes. It is likely the wheat referred to in the Torah and was a staple grain of ancient Egypt.
Einkorn and Emmer, even if threshed without heat, barely rise, even when using modern day yeasts, which are strong and predictable. The best you can get is a thick flatbread, perhaps four inches in height. By contrast, modern wheat and modern yeast when combined will cause the wheat to double in volume, and bread like the bread we are all familiar with can be made.
The ancient Egyptians discovered how to cause bread to rise. But for that to happen, wheat had to undergo another change.
About 8,000 years ago, Emmer was crossed (probably naturally) with another grass in the Levant. The new wheat, called Bread Wheat, has 42 chromosomes and was somewhat easier to thresh. It also had the ability to rise more closely to the way we associate with bread.
But it took a very long time for that wheat to take hold. It was only when the ancient Egyptians found out that the addition of ale or beer – or, later, sourdough starter – to bread dough made from Bread Wheat that had been threshed with no heat, and then allowing that yeast-infused dough to rest for several hours or overnight before baking, allowed the bread dough to significantly rise. That created a lighter, less dense bread that was known throughout antiquity as Egyptian Bread.
This technology – which even later included a new type of oven to maximize the bread's ability to rise – was a closely guarded secret of Egyptian nobility for at least 1000 years and raised Egyptian Bread was a very expensive commodity.
(The imprisonment of Pharaoh's baker and cupbearer followed by the execution of the baker and the release from prison and restoration to his position of honor of the cupbearer may be an early memory of the way the secret of raised bread spread from Egypt or, more likely, an anachronistic allegory to explain that spread.)
Ancient Israelites fleeing Egypt are very unlikely to have possessed either Bread Wheat, Bread Wheat dough, or the proper oven to bake raised bread, and the evidence is that most peoples of the region – including ours – ate soft unleavened flat breads made from Emmer (or even Einkorn) well into the era of the Second Tempe.
Unleavened bread was (and still is) the bread of shepherds and nomads.
When raised bread finally did spread out out of Egypt it became the bread of city dwellers throughout the Levant who were members of the upper and middle classes.
It is likely that disparity that caused matzah to be called lechem oni, poormen's bread or bread of affliction.
And that is probably really why it was adopted as the only bread allowed to be eaten during Passover, a holiday celebrated the escape (real or not) of slaves from Egypt who would wander in a desert for 40 years.
Even though we now have cities and farms, the logic would have gone, even though we are now settled on our own land and 'modern," we were once poor escaped slaves who wandered for decades through a harsh wilderness. We were poor (at least of land), but we were free.
So like sitting and living in a sukkah would later become a yearly tool to remember those 40 years of wandering in the wilderness, the ban on all modern raised bread would become a yearly tool to remember that we once were outcasts and slaves. In our antiquity as a people, our God saved us from slavery and oppression by the most powerful, modern nation in the ancient world – a nation heralded throughout the known world of antiquity for its closely guarded discovery of raised "modern" "Egyptian bread."